carville



UNITED STATES PATENT OFFICE.

GEO. B. MIGKLE AND J. M. CARVILLE, OF NEW YORK, N. Y.

EXTENSION-LADDER.

Specification of Letters Patent No. 27,821, dated April 10, 1860.

To all whom 'it may concern:

Be it known that we, GEORGE B. MICKLE and J. M. CARvlLLn, both of the city, county, and State of New York, have invented certain new and useful Improvements in Extension-Ladders; and we do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawing, forming a part of this specification, in which- Figure 1 represents a longitudinal vertical section of our invention, the line a2 w Fig. 2 indicating the plane of section. Fig. Q. is a front elevation of ditto, and Fig. 3 a longitudinal central section of our device for raising and lowering the ladders, in an enlarged scale.

Similar letters of reference in the three views lndicate corresponding part-s.

The object of our invention 1s to arrange a series of ladders in such a manner that they can be readily extended to any length when used in combination, and that they can be detached from each other with facility, and used singly as occasion may require.

Our invention consists, first, in arranging a series of ladders, one on the top of the other, and of decreasing width and length, with flat guide strips, and suitable stops in such a manner that said ladders can be used in the manner of an extension ladder, if it necessary to reach to a great height, or that each of the ladders can readily be taken olf and used singly in the manner of a common ladder; and it consists, second, in combining with said sliding ladders, two drums, arranged on one shaft in such a manner that by rotating either one or the other of said drums, either one of the ladders can be raised or lowered, singly or both combined,l

as will be hereinafter more fully explained.

To enable those skilled in the art to make and use our invention, we will proceed to describe its construction and operation, with reference to the drawings.

A, B, C, are three ladders, placed one 0n the top of the other, and of decreasing width and length, so that the side beams b, of the ladder B, lit nicely between the side beams a, of the ladder A, and in the same manner, the beams c, of the ladder C, lit between the beams Z), of the ladder B; as clearly shown in Fig. 2. Narrow guide strips cl, e, are attached to the lower ends of the beams of each of the ladders B, and C, of such a width that they extend about half way or less, over the width of the beams of the preceding ladder, and the length of these strips is in proportion to the length of the ladder to which they are attached. On the upper ends of the beams of the ladders A and B, are the stops f, g, arranged in such a manner that when the next succeeding ladder slides up on the preceding one, the stops of the latter come in contact with the guide strips of the former, and prevent the ladders being extended any farther than safety will admit.

The ladders B, and C, are raised by means of ropes it, and z', which are connected to the bottom rungs j, and 7e, of said ladder, and in order to detach said ropes with facility, the rungs are furnished with loops Z, m, and hooks a, o, are secured to the lower ends of the ropes, so that they.

can be hooked or unhooked in an instant. The rope t, of the ladder B, extends from the bottom rung j, over a pulley p, which is attached to the top rung of the ladder A, and down to a drum D, which is secured to a shaft a, that has its bearings in journal boxes o', attached to the under side of the beams a, and near to their butt ends, and it is rotated by means of a gear c', d', and crank cf, or in any other convenient manner. The rope z', of the ladder C, on the other hand extends from the hook 0, on the bottom rung 7c, of said ladder over a pulley g, on the top rung of the ladder A, being guided in its course by a pulley r on the top rung of the ladder B, and it Ais secured to a drum E, which is placed loosely 'on the shaft a, and one end of this drum is turned down, forming a ournal that runs in one of the boxes 6. This drum is rotated by a gear f', g, and a crank It', similar to the gear, whereby the drum D is operated. Braces F, attached to the side beams ax, of the ladder A serve to Steady the same either singly or together with the two other ladders in the usual manner.

If it is now desired to extend the ladders, both the drums D, E are rotated in the same direction, and the ladder B is caused to slide up the ladder A, until the guide strips (Z, comevin contact with the stops f. The motion of the drum D is now stopped, and that one of the drum E, is continued until the guide strips e, of the ladder C, come in contact with the stops g, of the ladder B. If, on the other hand it should be desirable to use either one of the ladders detached from the rest, the hooks and n are 'released from the loops m, and Z, and the ladders C, and B, can be taken off without difficulty.

We are aware that extension ladders have been constructed before, with such, however, the several ladders are connected by guides in such a manner that neither one of the ladders can be used singly. It is also well known that extension ladders have been constructed of two separate devices for raising and lowering the ladders, such, however, are attached to the bottom ladder on separate places, whereby the side beams of said ladder are weakened, and furthermore, the weight of two separate devices makes the ladder or ladders diliicult to handle.

Our ladders, on the other hand, can be sed either in combination or detached,- as may be desired, and the weight of the bottom ladder is but slightly increased by the two drums, and the strength of the side beams is preserved as much as possible.

hat we claim as new, and desire to secure by Letters Patent, is-

In combination with the drums D, E, on the shaft a', the ladders A, B, C, sliding strips el e and stops g f, substantially in the 4manner and for the purpose specified.

GEORGE B. MICKLE. J. MARSHALL CARVILLE. Witnesses J. W. CooMs, A. O. ALCooK. 

